static int
my_open(const char *file)
{
lock_acquire(&filesys_lock);
if(file == NULL){
lock_release(&filesys_lock);
return -1;
}
if(!address_valid(file)){
lock_release(&filesys_lock);
my_exit(-1);
}
struct file *fp = filesys_open(file);
int fd = thread_current()->fd;
if(!fp){
lock_release(&filesys_lock);
// printf("file open error\n");
return -1;
}
struct Elf32_Ehdr ehdr;
if (!(file_read (fp, &ehdr, sizeof ehdr) != sizeof ehdr
|| memcmp (ehdr.e_ident, "\177ELF\1\1\1", 7)
|| ehdr.e_type != 2
|| ehdr.e_machine != 3
|| ehdr.e_version != 1
|| ehdr.e_phentsize != sizeof (struct Elf32_Phdr)
|| ehdr.e_phnum > 1024))
{
file_deny_write (fp);
}
file_seek(fp, 0);
struct process_file *pf = malloc(sizeof(struct process_file));
pf->file = fp;
pf->fd = fd;
(thread_current()->fd)++;
list_push_back(&thread_current()->file_list, &pf->elem);
lock_release(&filesys_lock);
return fd;
}
/* Opens specified file. Returns its file descriptor. Same file opened
multiple times returns different file descriptors. A process has an
independent set of file descriptors (files open in that process). fd = 0 is
STDIN_FILENO, fd = 1 is STDOUT_FILENO - These are never returned here.
If file could not be opened, -1 is returned. */
static int
sys_open(const char *file)
{
check_mem_ptr(file);
if (file == NULL)
sys_exit(ERROR);
lock_acquire(&secure_file);
struct file *fl = filesys_open(file);
if (fl == NULL)
{
lock_release(&secure_file);
return FD_ERROR;
}
struct thread *t = thread_current();
/* Freed in sys_close(). */
struct proc_file *f = malloc(sizeof(struct proc_file));
if (f == NULL)
sys_exit(FD_ERROR);
list_push_front(&t->files, &f->file_elem);
f->file = fl;
/* If file is currently being run as an executable in this process, we must
not be able to write to it. */
if (is_executable(file))
file_deny_write(f->file);
int file_descriptor = t->next_file_descriptor;
f->fd = file_descriptor;
/* Increment next_file_descriptor so that the next file to be
opened has a different file descriptor. */
t->next_file_descriptor++;
lock_release(&secure_file);
return file_descriptor;
}
